I really love this puzzle design idolatrous! The hints are often very subtle and then it suddenly makes "Click!" in the head, when one comes across the solution. The discovery of the library with all its peculiarities has given me a lot of fun. :) That's why I wrote a recommendation article for your game on our blog and also uploaded a playthrough video for all those poor souls who are already standing frustrated in front of all these bookshelves. :D Good luck with the ratings at Ludum Dare 42, I hope for a high ranking for you. <3